This Is Us solidified its position as the breakout new hourlong series of the fall 2016 broadcast season with a big Live+3 lift. The premiere of the ensemble dramedy added a +1.38 adults 18-49 rating between Live+same day and Live+3, the biggest for any new series on any network in 20 months, since the debut of Fox mega hit Empire, which logged a L+3 gain of +1.48 in January 2015. With the +49% 18-49 lift, This Is Us, which already topped the Live+Same Day standings for…